In June 1846, following the U.S. annexation of Texas and the Mexican declaration of war, General Stephen Watts Kearny rode out of Fort Leavenworth with 2,000 soldiers, bound for California with orders to occupy Mexican territory. When his expedition ended a year later, the country had doubled in size and now stretched from the Atlantic to the Pacific, fulfilling what many saw as the nation's manifest destiny, while also setting the stage for the American Civil War. Winston Groom, author of Forrest Gump and co-author of the Pulitzer Prize finalist Conversations with the Enemy, recounts the amazing adventure and danger that Kearny and his troops encountered on the trail—a story that intertwines with those of Kit Carson, Brigham Young and his Mormon followers, and the ill-fated Donner party, trapped in the snows of the Sierra Nevada.